1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display. More particularly, it relates to a thin film encapsulated OLED display.
2. Description of the Related Art
An OLED display has self-luminance characteristics, and the thickness and weight thereof can be reduced since it does not require a separate light source, unlike a liquid crystal display (LCD). In addition, since the OLED display exhibits high-quality characteristics such as low power consumption, high luminance, high response speed, etc., it is receiving much attention as a next-generation display device.
The OLED display includes a plurality of OLEDs respectively having a hole injection electrode, an organic emission layer, and an electron injection electrode. When the anode and cathode inject holes and electrons into the organic light emitting layer, the OLEDs emit light using energy generated when excitons generated by electron-hole combinations in the organic light emitting layer are dropped from an excited state to a ground state, and an image is displayed when the excitons are dropped from an excited state to a ground state.
However, the organic emission layer is sensitive to external environment factors such as moisture and oxygen so that quality of the OLED display may deteriorate when being exposed to the moisture or oxygen. Therefore, in order to protect the OLEDs and prevent permeation of the moisture and oxygen into the organic emission layer, an encapsulation substrate is sealed to a display substrate where the OLEDs are formed through an additional sealing process, or a thick protection layer is formed on the OLEDs.
However, when the encapsulation substrate is used or the protection layer is formed, the manufacturing process of the OLED display becomes complicated to perfectly prevent permeation of the moisture or oxygen into the organic emission layer and the entire thickness of the OLED display cannot be formed to be slim.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.